Adjustable exercise step for aerobic exercise



FIG. 1 is an upper side perspective view of an adjustable step for aerobic exercise showing my new design;

FIG. 2 is a bottom side perspective view showing my new design; and

FIG. 3 is a side elevational view thereof;

FIG. 4 is a bottom plan view of the top member with the ribs outside showing my new design; and,

FIG. 5 is a top plan view of the base with the ribs inside thereof. 

The ornamental design for an adjustable exercise step for aerobic exercise, as shown. 